St Peters also capitalised, beating Brecon 31-6 to jump up to second, while at the other end Fairwater earned what could turn out to be a vital bonus point as they lost 18-14 at Llanishen.
Ian Davies was in sparkling form again for Division Two East leaders Gilfach Goch. The full-back landed a perfect seven-out-of-seven kicks as the Goch won 33-15 at Llantrisant.
But they may rue the missed bonus point as Mountain Ash closed the gap to nine points with a 35-7 victory over Ynysybwl, thanks in large part to two tries apiece by Gavin Roberts and Thomas Pascoe.
There was also double-delight for Treorchy wing Peter Hutchings, who bagged a brace as the promotion-chasers beat Llantwit Fardre 39-25.
Newport Saracens might yet escape the drop after a nervy 20-19 win at Rhydyfelin, while fellow strugglers Penallta beat Garndiffaith 31-18.
Abergavenny may lead Division Three East by 11 points but they were made to earn victory by Newport HSOB.Tries by wing Will Williams, number 8 James Williams, and centres Stuart and Ian Davies scraped them home, 24-14.
The ever-brilliant Paul Emanuelli was again the hero for second-placed Fleur de Llys, kicking 19 points as they beat Croesyceiliog. Wing Jamie Henthorn crossed twice to seal the 29-24 win for Fleur, who have four games in hand on the leaders.
Dowlais are champions-elect of Division Four South East after they beat Dowlais 28-10 and rivals Cardiff HSOB went down 30-25 to Taff's Well.